kunit: Introduce _NULL and _NOT_NULL macros

Today, when we want to check if a pointer is NULL and not ERR we have
two options:

KUNIT_EXPECT_TRUE(test, ptr == NULL);

or

KUNIT_EXPECT_PTR_NE(test, ptr, (struct mystruct *)NULL);

Create a new set of macros that take care of NULL checks.
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: Daniel Latypov <dlatypov@google.com>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

include/kunit/test.h

@@ -1218,6 +1218,48 @@ do {									       \
 				   fmt,					       \
 				   ##__VA_ARGS__)
 
+/**
+ * KUNIT_EXPECT_NULL() - Expects that @ptr is null.
+ * @test: The test context object.
+ * @ptr: an arbitrary pointer.
+ *
+ * Sets an expectation that the value that @ptr evaluates to is null. This is
+ * semantically equivalent to KUNIT_EXPECT_PTR_EQ(@test, ptr, NULL).
+ * See KUNIT_EXPECT_TRUE() for more information.
+ */
+#define KUNIT_EXPECT_NULL(test, ptr)				               \
+	KUNIT_EXPECT_NULL_MSG(test,					       \
+			      ptr,					       \
+			      NULL)
+
+#define KUNIT_EXPECT_NULL_MSG(test, ptr, fmt, ...)	                       \
+	KUNIT_BINARY_PTR_ASSERTION(test,				       \
+				   KUNIT_EXPECTATION,			       \
+				   ptr, ==, NULL,			       \
+				   fmt,					       \
+				   ##__VA_ARGS__)
+
+/**
+ * KUNIT_EXPECT_NOT_NULL() - Expects that @ptr is not null.
+ * @test: The test context object.
+ * @ptr: an arbitrary pointer.
+ *
+ * Sets an expectation that the value that @ptr evaluates to is not null. This
+ * is semantically equivalent to KUNIT_EXPECT_PTR_NE(@test, ptr, NULL).
+ * See KUNIT_EXPECT_TRUE() for more information.
+ */
+#define KUNIT_EXPECT_NOT_NULL(test, ptr)			               \
+	KUNIT_EXPECT_NOT_NULL_MSG(test,					       \
+				  ptr,					       \
+				  NULL)
+
+#define KUNIT_EXPECT_NOT_NULL_MSG(test, ptr, fmt, ...)	                       \
+	KUNIT_BINARY_PTR_ASSERTION(test,				       \
+				   KUNIT_EXPECTATION,			       \
+				   ptr, !=, NULL,			       \
+				   fmt,					       \
+				   ##__VA_ARGS__)
+
 /**
  * KUNIT_EXPECT_NOT_ERR_OR_NULL() - Expects that @ptr is not null and not err.
  * @test: The test context object.
@@ -1485,6 +1527,48 @@ do {									       \
 				   fmt,					       \
 				   ##__VA_ARGS__)
 
+/**
+ * KUNIT_ASSERT_NULL() - Asserts that pointers @ptr is null.
+ * @test: The test context object.
+ * @ptr: an arbitrary pointer.
+ *
+ * Sets an assertion that the values that @ptr evaluates to is null. This is
+ * the same as KUNIT_EXPECT_NULL(), except it causes an assertion
+ * failure (see KUNIT_ASSERT_TRUE()) when the assertion is not met.
+ */
+#define KUNIT_ASSERT_NULL(test, ptr) \
+	KUNIT_ASSERT_NULL_MSG(test,					       \
+			      ptr,					       \
+			      NULL)
+
+#define KUNIT_ASSERT_NULL_MSG(test, ptr, fmt, ...) \
+	KUNIT_BINARY_PTR_ASSERTION(test,				       \
+				   KUNIT_ASSERTION,			       \
+				   ptr, ==, NULL,			       \
+				   fmt,					       \
+				   ##__VA_ARGS__)
+
+/**
+ * KUNIT_ASSERT_NOT_NULL() - Asserts that pointers @ptr is not null.
+ * @test: The test context object.
+ * @ptr: an arbitrary pointer.
+ *
+ * Sets an assertion that the values that @ptr evaluates to is not null. This
+ * is the same as KUNIT_EXPECT_NOT_NULL(), except it causes an assertion
+ * failure (see KUNIT_ASSERT_TRUE()) when the assertion is not met.
+ */
+#define KUNIT_ASSERT_NOT_NULL(test, ptr) \
+	KUNIT_ASSERT_NOT_NULL_MSG(test,					       \
+				  ptr,					       \
+				  NULL)
+
+#define KUNIT_ASSERT_NOT_NULL_MSG(test, ptr, fmt, ...) \
+	KUNIT_BINARY_PTR_ASSERTION(test,				       \
+				   KUNIT_ASSERTION,			       \
+				   ptr, !=, NULL,			       \
+				   fmt,					       \
+				   ##__VA_ARGS__)
+
 /**
  * KUNIT_ASSERT_NOT_ERR_OR_NULL() - Assertion that @ptr is not null and not err.
  * @test: The test context object.